ALDOSEAL 399 is a high solid, low VOC, one-part silicone elastomeric flashing grade specifically designed for use in sealing roof penetrations, curbs, seams, flashing areas and any other roof top areas of possible water infiltration. ALDOSEAL 399 is also the sealant of choice for any roof system that has been previously coated with a silicone elastomeric coating. Once applied, this silicone flashing grade provides a durable, seamless and flexible system that resists lateral movement, shear and will allow for normal expansion and contraction. Mil for mil, ALDOSEAL 399 provides greater waterproofing protection than similar flashing grade silicone sealants and offers excellent resistance to moisture penetration.